“Is Mormonism Christian?” can be answered only by knowing what standard the inquirer uses to grant institutions status as Christian. Early Mormon documents reveal that Mormons, like everyone in the early American religious marketplace, were obliged to define their differences from others. Perceptions about Mormonism’s relationship to other Christian churches have shifted over time, both from within and outside the LDS Church. Other Christian churches now see Mormonism as a partner in family values and lifestyles, but stark theological differences still divide them. Mormons have distinct scriptural texts, a history of polygamy, and temple worship, and even Mormon architecture creates an identity. Modern Mormons’ focus on Christ and humanitarian service signal an end to the need to segregate themselves from other denominations.